Automatic telephone exchange



-March 25 ,i 1924. 1,487,87@

F. A. LUNDQUIST AUTOMATIC TELEPHONE EXCHANGE Filed oc't. 27. 1919 7 sheets-sheet 2 y @of y March 25 1924.

A 1,487,870 F. A. LuNDQuls'r AUTOMATIC TELEPHONE EXCHANGE Filed Oct. 27, 1919 7 Sheets-Sheet 3 March 25 1924.

RASZS'F@ E. A. LUNDQUIST AUTOMATI C TELEPHONE EXCHANGE Filed oca-27, 1919 '7 sheets-sheet 4 March 25 1924. 1,487,870

n F. A. LUNDQUIST 'AUTOMATIC TELEPHONE EXCHANGE Filed oct. 27,1919

'7 Sheets-Sheet 5 March 25 1924.

F. A. LUNDQUIST AUTOMATIC TELEPHNE EXCHANGE 7 sheets-sheet e Filed OC't. 27 1919 Mmm-25,.1924. 1,487,870

F. A.. L uNDQUlsT' n AUTOMATIC TELEPHONE EXCHANGE.'

Filed oct. 27., 1919 '7 sheets-sheet v Patented Mar. 19241.

FRANK A. LUNDQUYIST, OE CHICAGQ, LLENOIS, .SSGNOR, BY MESSER ASSIGNMENTS, TO HENRY S. CONRAD, TRUSTEE.

AUTOIEATIC TETJEPHGNE EXCHiNGE.

Application led October 27, 1919.

To all 107mm t may concern:

it known that l, FRANK A. LUND- Qtusfr.l a citizen ot the United cSntates et America, and a resident ot Chicago, county o' Cooley and State orp illinois, have invented certain new and useful improvements in iutomatic Telephone Exchanges, ot which the following is a specification.

Mv .invention relates to automatic telephone exch anges, and has tor itsobject mprovements in such organizations. The present invention is confined to the parts et the exchange which are employed in the preliniinary stages ot making a call.

the accompanying drawings- Fig. 1 is side elevation of one of the line switches and associated parts in malring a trunk selection;

2 is an enlarged section on line 2 2 et Fig. 1, together with some additional parts;

IFig. or the Fig. 3;

Fig. 5 is an elevation in the direction 5 of Fig. 1, showing one line switch and a part of a second one together with additional apparatus in diagram for a group of one hundred line switches; and

6, 7, 8, 9 and 10, taken together, with il" g. 6 fthe hottoin and Fig. 1() at the top, 'torni a general diagram or" the electrical and pneumatic connections for one thousand line switches.

3 is a side elevation of a 'fragment apparatus on a selector;

41T is an end elevation of a part of Referring i'irst to Figs. 1 and 2, on the hase 11 is a hollow standard 12., and on this is mounted tubular cap 13 tree to slide on the standard when compressed air is admitted or enhailsted thru the pipe 14E. rlhese parts form pneumatic motor which will hereafter he referred to as motoril.

Secured rigidlj7 on the lower part of 13 is collar 15 ot insulating material, and slidahlv mounted thereon is a sleeve 16. iins 17 secured in the collar 15 and eX- tending thru slots 1S in the sleeve 16 limit the length of movement of the sleeve on the colla-r. A projection 19 on one side of the sleeve 16 extends downward and rests on a piece ot insulation when the line switch is in its normal or lower position.

ivoted at 21 on the projection 19 is a bell crank 22. the horizontal parts of which rest Serial N0. 333,514.2.

upon the pins 17. The vertical arm of the hell crank is hinged at 23 so that the upper part 241 of this arm may move at right an gies to the movement about the pivot 21. 1n Fig. 5 at the lower left hand portion, this hell crank is all that appears of the second line switch, the other parts'of this line switch being removed to show this View such line switches arranged in a row consti-' tute a group ot line switches.

Adj acent to such a group of line switches are pieces ot insulating material (Figs. 2 and 5), and

mounted to slide in slots in these pieces are horizontal hars 31. Adjacent to pieces 30 are mounting plates 32 on which are supported sylphons 33, each connected to a diii'crenthar 31. svlphon is a metallic device similar to an accordion which enpands and contracts as air is admitted to or exhausted therefrom.

rlie hars 31 thin flat strips which have one edge notched so as to leave projecting parte 34 shown in Fig. 2. lnone corner oit each projection 311 is a hole 35 of a size and shape to receive the pin 25 on the part 21.1 ot hell crank 22. ihen the sylphons are in their contracted position, the bars 31 are supported so that the holes 35 in each are arranged vertically over each other and opposite the centers et the motors 13. When a svlphon is expanded, the connected bar is shifted in the direction of the arrow so that its notches between projections 34 are opposite the centers of the motors 13.

Secured to each piece or plate 30 is a toothed har 36 arranged to he engaged bv Athe hook 26 whenever the part 24 of hell crank 22 moi/'espn its hinge 28. `When compressed air is admitted to th motor 13, the collar 15 rises with the motor, hat the sleeve 16 remains supported on the block 2() until the pins 17 reach the upper end oi' the slots 18. Vhen this occurs, the

sleeve 16 and parts supported thereon rise with the motor. In the preliminary movement in which the pins 17 travel in slots 18, the bell crank is turned on its pivot so that pin 25 is moved to a position directly under the adjacent vertical row ot holes o5 in bars 31. 1t the lowest bar 31 is in its normal position, then pin 25 will enter hole 85, and the upward movement ot the motor 13 will be arrested by contact between the bar 31 and the upper end ot the part 2l ot bell crank Q2. it, however, thc lowest bar has been shiitted by its sylphon, then the adjacentprojection will not be in the path ot the bell crank, and the motor 13 will continue to rise until the bell crank finds some other bar B1 which'has not been shifted. lt, a'ttcr engagement between a bell crani; and a bar 31, the bar is shifted by its sylphon 33, then the engagement between the pin 25 and hole 35 will move the part Qlion its hinge 23 so as to cause the hook 26 to engage toothed bar 3G.

It is to be observed that it the lowest bar S1 is in its normal position. then any one ot the adjacent line switches in rising will engage it and be stopped in that position. But if the lowest bar has been moved by its sylphon, then no line switch can engage it. Any rising line switch would pass the lowest bar and be stopped by the second bar,V or by the first bar it iound in its normal position.

rEhe trunk terminals are metallic strips arranged in pairs insulated from each other. rthey are shown in transverse section in the upper right hand part of Fig. 1, and in side elevation in the upper part ot Fig. 5. The wipers 2S and 29 are shown in engagement with normal contacts which are alive torY certain conditions but which are dead as tar as the present application goes. Above the contacts l0 are t wenty pairs oi terminals Ll1 which correspond to the twenty bars 31 and the twenty teeth on the racks fr group ol twentybars and a group ot twenty pairs ot terminals extend adjacent to a group oi one hundred line switches. and terminate where the group ot line switches terniinates. Similar gronps ol" bars and terminals are associated with each group of one hundred line switches. Sonie of the bars and terminals ot one group are associated electrically a id pneuinatically with corresponding bars and terminals ot other groups, but they are separated mechanically/i'.

AssociatedL with and forming part ot each line switch are a line relay having windings l2 and 51, a valve 53, a motor 7l and certain other parts which will be understood from the description oit the ope ation The wires t6 and L17, at the lower right hand part ont Fig. 1 extend to a local station where they are provided with means for being electrically connected to complete a circuit thru the line relay. l/Vhen this occurs a current This attracts armature 52 to open valve 53 and permit compressed air to flow; from the general supply pipe 54- thru pipe 11i to the motor 12:3 which innnediately risespn this niovenient upward the bell crank 22 is tilted forward as previously described and engage the first bar 31 found in its norinal position. ll will be assnn'ied that this is Vthis time the lowest bar indicated by the numeral 6d, whereupon a circuit is completed which may be traced on 6 as follows: battery Y- 55--56-57-5S5960-6l-inagnet Y 62+ (-tiet-2;ground.

This attracts Ythe armature 65 which is caught and held by the hook 6G which breaks the circuit tor the magnet (S2 at the springs ati-57. 'ihe ni'oveinent ot thearmature 65 opens the valve G7 so as to permit air to low from pipe tnru pipe 68 to the sylphon 33 which is connected to the bar @it or" Y the group 31.

adjacent to the magnet G2V is another magnet 71 which has a wire 72 extending to the spring '73 F ig. 3 on the particular selecjfor which is on the other end oit the trunk found by the stoppage ot the motor 13 when the bell crank 22 engages a bar 31. Then the hook 5G Fig. 6 nieves to catcharinature G5, the sni'tt in the adjacent Vcontact springs connects the battery Y Vto spring T3 as `follows: (Figs. 2, 3 and 6).

lllhen the sylphon operates by reason of armature 65 opening valve 67 as described, it inoi'es Vthe. associated bar longitudinally and causes the'hooli 25 on the part 2i to engage the teeth .ot the associa-ted racl?` 3G.V

'When the opening ot valve admitted air to motor 13 it also admitted air to motor VTet which is one branch of pipe 1li. But motor 'T-l is restrained by a stiit spring 75. Under these conditions. motor 7-1 will not operate as long as air tiows freely to rising motor 13, but as'soon as motor 1? is stopped byV reason otits bell crank 22 engaging a bar 3l. Jfull pressure will tiow to motor 'llland that motor will advance until hooi; 7G drops over the ring 71. l/Vhen this occurs, the adjacent contact springs .move to their alter- Vnative position and the station wires 116 and et? are shifted from the VlineV relay to the wipersV and 29. These wipers are at this time onv the vterminals olf 'the found trunk 'epresented by wires 78 and 79.

On each trunk at the selector is a relay corresponding to the line'relay l2-51, and this relay is energized when the line wires 'Ll-t3 and '-17 are connectedto the wipers'28 and 20 in the saine way'that the relay 2 51 was previously energized. The relay thus energized on the selector opens Va valve cor-V responding to valve 53, and this admits air to the inotor 8() shown in Fig. 3. Y This motor Vicc Y 1' ,esmero lifts arm 31 to raise cam 3:2 above the pin 33 on spring 73. These parts are held in this position until release occurs.

lNhen` the dropping ot catch 76 Fig. 1 shifted the line wires to the wipers 23 and 29, it broke the circuit tor the relay 42-51, and this in turn permitted the valve 53 to close and shutair trom motors 13 and 7st. But motor 1 3 is held by the previous engagement of hook 26 on ratchet 36, and motor 741 is held by catch 76 on ring 77. Consequently, the breaking` ot the circuit thru the line relay does nothing other than sluit oit the flow of electricity thru the relay and the flow ot air to motors 13 and 74;.

lVhen the subscriber breaks'the circuit at his station, the motor 8O on the selector italls back and in part. ot the descent ot the arm 81 causes cam 32 to engage pin 33 and move spring` 73 to engagement with groundw ed spring 84e. When this occurs a current iows as Jfollows: Y in Fig. 6-55--56-69 ---(Figs. 6 and 2)-71-72-(Figs. 6, 2 and 3 -73811-ground- This attracts armature 85 and causes it to release hook 66 trom armature 65 which falls back and permits valve 67 to close; this shuts air from the sylphon 33 and permits spring 36 (Figs. 2 and 5) to return the moved bar 31 to its normal position. The return of this har releases hook Q6 from rack 36 and permits motor to fall to normal position. In thus falling, the projection 87 (Fig. 1) engages the tail oi' catch 76 tolitt it from ring 77 and permit motor 74 to return to normal.

At the time the armature 85 moves the hook 66 from armature 65, it breaks the circuit for magnet 71 at springs 56-69, but at the same time remakes it at springs 87 88. when the circuit is: Y-55-37-38- 7071-72-73--( Fig. S4-ground.

In arranging an exchange ot one thousand subscribers l place the line switches in ten groups of one hundred each. When the line switches are measured by the trunks leading from them, the grouping is composite. For certain of the trunks. the line switches are in ten groups ot' one hundred each. for certain other trunks, the switches are in tive groups of two hundred each; for still other trunks they are in two groups of tive hundred each; and for a fourth class ot trunks the switches are all in one group. Two or more trunks ot each class are available tor each line switch in the exchange, and Figs. 1 and 5 show a tota-l ot twenty trunks for each switch, This means that the present .illustration is o't twenty trunks divided into four classes of two or more in each class. In Figs. 6 to 10 l have shown two trunks for each class, the trunks being arranged `tor ten groups ot line switches. lt is to be understood that the actual trunks ot each class can be increased to any desired number, the two shown in each class being suiiicient to make clear the manner ot arranging them. 1t is also to be understood that the terminals 11 are arranged the bars 31 are arwires leading from are the three wires in. the same way that ranged, and that the strips 11 and bars 31 of a trunk. Also that, associated with each such three wires is an electrical and pneumatic unit such as shown in Fig. 2.

ln the lower part ot Fig. 6 there are shown eight bars 31 together with the sylphons by which they are moved. rThese eight represent two bars ot each class. Below these bars are shown the electrical devices for one bar, it being understood that there are one hundred line switches in 'front of these bars. For convenience l designate the one hundred line switches in iront oit a distance covered by the length ot a bar as a group of line switches, and the twenty bars (eight only shown) adjacent to the switches as a group ot bars. But the division of these bars as will be explained, l call a division into classes.

In the upper part of Fig. 6 is a second group ot bars 31 with which there is. ot course, associated a group of one hundred line switches Similarly, on each oi the other diagram sheets are two groups ot bars, and their connections.

Referring to the trunks of the first hundred in the lower half o'lFig. 6, the lowest two bars 31 represent trunks which are limited to this hundred switches, and consequently the bars have no wires leading to other groups. Taking the next two bars 31 just above those mentioned, they have wires 90 and 91 leading to correspending` bars 31 in the second group on the upper halt oit Fig. 6. Consequently, while these bars of these two `groups are mechanically separated they are electrically connected.

Taking the next two bars. it will be seen that they have wires 92 and 93 which may be traced. thru Fig. 7 and the lower halt ot 3. in all. ot which places these wires have taps leading to corresponding located bars. rThis means that these bars in .tive ditterent groups are electrically connected so that an electrical connection ma de to any one ot them extends to all of the others.

The upper two bars have wires 94: and 95 which extend over the entire thousand and have taps connected to the upper two hars of each hundred. An electrical connection made to either bar in any of these groups extends to corresponding bars in all of the other groups.

In each ot the other groups, the lowest two bars have no electrical connections extending to other groups, and consequently they are individual to 'their own groups. The second two bars ot the third and fourth hundreds are connected together by wires 96 and 97; the corresponding bars of the fifth and sixth hundreds are connected by wires 98 and 99; those of the seventh and eighth by wires 100 and 101; and those of the ninth andrtenth by wires 102 and 103. The last live hundred have corresponding bars connected together by wires 104; and 105.

Each bar 31 has its own sylphon 38, with air connections to the general supply pipe 54;. Thewlowest two bars of each hundred each has its own valve 67 operated by its own magnet 62 for letting air flow to its own sylphon. .These are the bars which have no wires extending to corresponding bars in other groups. Consequently, each Vof these bars is independent, both electrically and pneumatically, of what happens to other bars.

The sylphons of the second two bars of the first and second hundreds are connected together by pipes 106 and 107; the corresponding sylphons of the third and fourth hundreds are connected by pipes 108 and 109; and other corresponding sylphons are connected by pipes 110 and 111, pipes 112 and 113, and pipes 114 andV 115. By comparisons it will be seen that the bars of different groups are interconnected pneumatically in the same way that they are connected electrically thru the wires previously described. Hence, it will not be necessary to describe all of the pipe connections in detail.V They can be traced on the drawings.

VThe pipe 107 receives air from the main pipe 54 thru a valve 67a which is operated by a magnet 62 associated with the trunk involved. A part of the armature of this magnet is shown at 65a. By inspection it will be seen that this pipe 107 connects to the third sylphon in both groups shown in Fig. 6, and that when the valve 67a is opened, the corresponding bars of both groups are shifted by their sylphons so that no moving line switch in either group willbe stopped by a bar in the third position. `These bars are the ones interconnected by the wire 91.

In the previous description it was assumed that the line switchof Fig. 1 was stopped by the first or lowest bar which was given the special reference character 64 to distinguish it from others Vfor convenience. Because this bar (and the next one above it) has no connection to any other group, it alone is shifted when air is admitted to the sylphon shown in Fig. 2. But if we assume that the lower two bars had been shifted and that the rising line switch had engaged the third bar, then the valve opened by the corresponding magnet 71 would admit air to the third sylphon of two groups. From this it will be apparent that one magnet 62 with corresponding valve is suflicient for the simultaneous movement of two or more bars when they have their sylphons connected to a pipe controlled by the valve. The connection 91 between the bars makes it evident that a wire such as G3 extending to the magnet 62 may come selector; the third bars of the third and fourth groups constitute part of another trunk; and soon. And the same thing is true of the fourth bars of the various groups as may be seen by the interconnecting wires and pipes. Y

ln the same way the fifth bars of the rst 'five groups constitute part of one trunk` and the sixth bars of the same groups constitute part of anotherY trunk. The same is true of the iifth and sixth bars of the last five groups. The seventh bars of all of the groups are parts of the terminals of one trunk.v and the'cighth bars are parts of the terminals of another trunk. Y

c A. point to be noted is that the release of a line switch is by the return movement of the bar 31 to which it has made connection, and that these bars are controlled by the valves 67, 67, etc., which admit air to the sylphons 33. These valves inY turn are controlled by the magnets 62, there beingl one such magnet for each valve. By inspection of the air connections on Figs. 6 to 10` it will-be seen that the magnets and valves involved in releasing the line switches are not as numerous as the switches to be released, and noteven as numerous as the bars to which the line switches make connection. The release mechanisms,

to which the switches connect, and some trunks terminate at several bars 31. VAny line switch may connect to the top bar of its group, and as all top bars are interconnected by wire and pipe and controlled by a` single magnet and valve, Vit is evident that every switch inV therthousand is capable of being released by theV same release mechanism.

What I claim is:

1. In a telephone exchange, a series of line switches, a movable element for eachof said line switches, a series of bars each of which has projections in the path of each of said elements when said elementsare moved from their normal positions, means for moving said elements `from their normal positions, a pneumatic device associated Ywith each bar for moving it so as to remove its projections from the paths of said elements, magnets associated with said bars .for controlling the admission of air to said pneumatic devices,

and means for closing the circuit for one ofA said magnets by contact between one of said elements and the bar with which said magnet is associated.

2. A line switch having an element arranged to be moved from normal position by air press-ure, a motor for moving said element, means tor stopping said element in connection with an idle trunlr, a pneumatic device for shifting the stopping means laterally when the idle trunlr is reached, and a catch operated by such lateral movement and serving to support said element in its operated position alter the air pressure is withdrawn.

3. ln a switching mechanism, wipers, a power device for moving them, a series of stopping devices any one of which when in normal position will stop the movement of the wipers and remove the source olf power therefrom, and a holding device operated by a stopping device and arranged to retain the wipers in arrested positionafter the power is removed.

4f. A motor, a series of stopping devices, an arm carried by the motor, and a sliding connection between the motor and the arm operated by the motor to move said arm toward or from the stopping devices.

5. A. series of groups of lineswitches and means for moving them, a series or' stopping devices for each group ot switches any device ol which will serve to stop the movement of any switch of its group, and means by which one engagement between a line switch and a stopping device will automatically cause the removal of corresponding stopping devices in two groups.

6. A group of line switches, a group of bars each of which has a projection in the path of each line switch when said line switches are moved from their normal positions, a series of such groups, means for moving any bar so as to remove its projections from the paths of the line switches, and means by which an engagement between a line switch and a bar will automatically cause the movement of that bar and a corresponding bar in another group so as to remove the projections of both from the paths or line switches.

7 A group of bars, a pneumatic device associated with each bar :for moving it from normal position, a series of such groups, and means by which an electrical connection made to one bar will cause the bar to be moved and also cause the movement ol? another bar in another group.

8. In a. line switch controlling apparatus, a series of groups of bars, a pneumatic device connected to each bar for moving it, interconnections between certain bars of one group and corresponding bars of other groups, and means by which upon a line switch engaging an interconnected bar the pneumatic devices of that bar and the one sin or more bars with which it is interconnected will operate to move their bars.

9. ln a line switch controlling apparatus, bars located at diierent places adjacent to the line switches to be controlled, a pneumatic device connected to each bar for moving it, an air pipe connecting two such pneumatic devices, a valve for admitting compressed air to said pipe, and means 'for controlling said valve by Contact of any line switch with either oi the bars having connected pneumatic devices.

10. ln a line switch controlling apparatus, bars located at different places adjacent to the line switches to be controlled, a pneumatic device connected to each bar for moving it, air pipes connecting certain pneumatic devices in pairs, an air valve connected to each pipe, electrical connections between bars corresponding to the pipe connections ietween pneumatic devices, and means for controlling each air valve by an electrical impulse flowing over the corresponding electrical connection.

11. In a line switch controlling apparatus, bars adjacent to the switches and serving to stop them, a motor connected to each bar and serving to move it from position in which it will stop a line switch, interconnections between certain motors so arranged as to cause a plurality of motors to operate simultaneously, and interconnections between bars to correspond with the interconnections between motors.

12. ln a line switch controlling appara-tus, hars *for controlling the line switches, a motor connected to each bar for moving it, interconnections between certain motors so arranged as to cause two or more of them to operate simultaneously, similar interconnections between bars, and means for con` trolling the motors thru the interconnections to the bars.

13. A. series of line switches, devices common to and controlling the series of line switches, a motor connected to each device for moving it, and interconnections for causing a plurality of motors to operate simultaneously.

14. A series of line switches, trunk terminals therefor, means for moving the line switches, devices Jfor stopping the line switches on a trunk terminal, and means for operating a plurality ot said devices simultaneously.

il series of line switches, trunk terminals therefor, devices which in their normal positions control the operation oit said line switches to select an idle trunk terminal, means for operating a plurality or" said devices simultaneously, and means for controlling such operation by a moving line switch.

16. A series of line switches, a series of dcvices each one of which` in its normal posidal).

Vstopping any line switch within a group on an idle trunk line, another device for stopping any line switch within a plurality of groups on an idle trunk line, and means by which upon a line switch engaging either ot said devices the engaged device will be automatically moved from normal position.

18. A series of vline switches divided into groups, a series of trunks having terminals at the line switches, said trunks being divided into classes part of which classes have terminals at a. plurality of groups ot line switches, and switch stopping devices divided 'into clases which correspond to the classes into which the trunks are divided, said devices in their normal positions adapt ed to stop the trunk hunting operation ot said line switches. Y

19. A series of line switches divided into groups, anda series of switch controlling devices divided into classes, one class ot' which corresponds to the groups and another class of which corresponds to a pluraility ot' groups, said devices in their normal positions adapted to. stop the trunk hunting operation of said line switches.

20. A series of line switches divided into groups, a series of switch stopping devices divided into corresponding groups, part ot' the switching stopping devices of one group being permanently connected to coresponding switch stopping devices of another group so that the stopping` devices become divided int-o classes which do not correspond to the groups, and means for controlling the stopI ping devices by the classes into which they are divided.

21. In a telephone exchange, the combination with a series of pneumatically operated line switches, a less numerous series of trunks, selector switches and means for operating the line switches to automatically select idle trunks, of a release mechanism separate from said selector switches andassociated with each trunk, and means by which the mechanism of aA trunk serves as a. means for releasing any line switch which may have selected that trunk.

2 2. ln a telephone exchange, a series ot pneumatic-ally operated line switches, a less numerous series ot trunks to which said line. switches may be connected, selector switches and arreleasing mechanism for each trunk separate trom said selec-tor switches, each releasing mechanism being arranged to release any line switch which may become connected to the corresponding trunk.

line switch may be released b anyone of a plurality ot mechanisms and t e same mechanism may release any one oit plurality of line switches. y

l 25. ln a telephone system, line switches Vdivided into groups, wipers and bank contacts for each switch, trunklines, one group or" said trunk lines connected to the banks ot' only one group of switches and another group connected to the banks of a plurality ont groups of switches, a stopping device comm-on to the trunks of'said rst group and a stopping device common to the trunks of the other group ior stopping the switches in engagement with one ojt said trunk lines.

26. ln a telephone system, two motors with a. common connection, a device for admitting a source of energy to said connection to causethe operation of said motors, one of said motors arranged to opera-te under a less amount' of ei'iergy than the other motor whereby said other motor does not receive enough energy to cause it to Aoperate until said first motor has had its movement arrested. u Y

27. In a telephone system, the combination of a motor having a variable movement, a second motor having a fixed movement and a device Vtor admitting a source of energy to both of said motors, ot means for retaining the second motor in unmoved position until after the first motor has completed its movement. r

28. In a telephone system, the combination with two motors having a comme-neonnection, ot' a device for admitting a. source ot energy to said common connection to operate said motors, Vand means tor holding one of said motors inoperative until the other of said motors has been moved and stopped.

29. In a telephone system, an automatic switch having two motors, a device forradmitting a source of energy to said motors at the same time tor causing the operation of said motors, and means for holding one of said motors inoperative until the other of said motors has been moved andfstopped.

30, In a telephone system,.a series of line Y nerr/,evo

connections for causing a plurality of motors to operaie simnlieneously.

31. in e telephone system, a series of line switches, trunk yterminals therefor, devices, common to said line switches, seid devices for stopping said line switches on :i trunk terminal, and means for opera-ting n plurality of said devices simultaneously.

32. in e telephone exchange, a series of line switches, a movable element on cecli of said line switches, e series of bars each of which has a projection in the path of each hay of said movable elements when said elements are moved from their normal positions, means :for moving said elements from their normal positions, a pneumatic device associrited with eac-li bar for moving it so es to remove its projections from the pat-lis of said elements, magnets associated with said bars for controlling the admission of air to said pneumatic devices, and means for energizing any one of said magnets.

FRANK A. LUNDQUIST. 

